Steering arrangement for mobile x-ray apparatus

ABSTRACT

A mobile X-ray apparatus has a carriage provided with at least one pair of independently driven driving wheels and a motor. The carriage includes a driving handle, which comprises sidebars, attached to a rotation axis solidly fixed to the carriage, and a crossbar, which is connected to the sidebars in an articulated manner to allow the turning movement of the sidebars about the said axis independently of each other. The apparatus also controls the operation of the motor by movements of the handle. The sidebars are provided with a toothed rim that moves along with the movement of the respective sidebar. The movements are measured by a potentiometer, which converts the movement into an electric signal by which the motor of the driving wheels is controlled.

CROSS REFERENCE TO RELATED APPLICATION

The present application is the U.S. national stage application ofInternational Application PCT/F100/00543, filed Jun. 16, 2000, whichinternational application was published on Jan. 11, 2001 asInternational Publication WO 01/01860 in the English languages. TheInternational Application claims priority of Finnish Patent applicationSer. No. 991487, filed Jun. 30, 1999.

SUMMARY OF THE INVENTION

The present invention relates to a mobile X-ray apparatus whichcomprises a carriage provided with at least one pair of independentlydriven driving wheels and their motor means, the carriage including adriving handle which comprises side bars and a crossbar extendingbetween them, the said apparatus in addition comprising means responsiveto the movement of the driving handle, which responsive means controlthe operation of the motor means in order to steer the carriage in thedesired direction.

The mobile X-ray apparatus comprises a carriage to which is connected anX-ray source, X-ray receiving means and the control electronicsrequired, and possibly a monitor for immediate examination of, forexample, digitally produced X-ray photographs. When accumulators areused as the power source of a mobile X-ray apparatus, the weight of theapparatus increases and may be, for example, of the order of 300 kg,which means that to make the apparatus lighter to move, the drivingmotion must be motorised. One way of controlling this type of amotorised X-ray apparatus is to provide a driving handle, the manualmoving of which provides control signals for driving the motor means ofthe driving wheels of the carriage, in order to steer the carriage inthe desired direction. One such solution is disclosed in U.S. Pat. No.4,697,661, in which the operation of the driving handle is based onconverting the movement of the driving handle into a bending movement ofthe cantilevered arms arranged in the vicinity of the driving handle,the bending movement causing the said control signals to be produced.One object of the present invention is to achieve a new type of mobileX-ray apparatus in which the movement of the driving handle can beconverted relatively simply and reliably into an electric signalcontrolling the control electronics of the motor means. An importantadditional object is to provide a motorised mobile X-ray apparatus whichis additionally arranged to be manually movable without the motor meansin exceptional situations.

BRIEF DESCRIPTION OF THE INVENTION

In order to achieve the objects of the invention, the mobile X-rayapparatus relating to the invention is characterised in that the sidebars of the driving handle are attached to a rotation axis solidly fixedto the carriage, so as to turn about the axis; that the side bars andthe crossbar are connected to each other in an articulated manner toallow the turning movement of the side bars about the said rotation axisto different extents and/or in different directions; that the side barsare provided with means which move along with the turning movement ofthe respective side bar each time, and the movement of which means ismeasured by measuring means which convert the movement of the said meansinto an electric signal by means of which the operation of the motormeans of the driving wheels is controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail below, with reference tothe appended drawing, the only FIGURE of which shows a diagrammatic sideview of the carriage part of the X-ray apparatus, without the actualX-ray imaging devices to be included in it.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the figure, the carriage comprises driving wheels 17,of which there is one on either side of the carriage and which aredriven each time by means of a driving motor 12 via belts 13, 15. Belt15 is tightened by means of tension springs 11 and a jockey pulley 18connected to them for transmitting the rotary movement of the drivingmotor 12 via the belt pulleys 14, 16 to the driving wheel 17. Theoperation of the driving motor 12 is controlled by means of a drivinghandle which comprises side bars 2 and a crossbar 1 attached betweenthem in an articulated manner. The side bars 2 are attached to arotation axis 3 solidly fixed to the carriage to make possible theirturning movement about the rotation axis 3. In the embodiment shown, tothe rotation axis 3 end of the side bars is connected a part 4 of atoothed rim which moves together with the side bar 2 during the turningmovement. This turning movement of the toothed rim 4 is measured, forexample, by measuring means 10 realised as a potentiometer, which meansconverts the said movement into an electric signal which is fed to thecontrol electronics of the driving motors 12 in order to drive thedriving motors to steer the carriage in the desired direction. Thearticulated joint between the side bars 2 and the crossbar 1 allows aturning movement of the side bars 2 to a different extent and, ifnecessary, in a different direction about the said rotation axis 3 inorder to make possible the desired direction of travel. When drivingstraight (forwards or backwards), the driving wheels rotate at mutuallythe same speed and in the same direction, but when turning left orright, one of the driving wheels must rotate slower than the drivingwheel on the other side, or the driving wheels must rotate in differentdirections.

In case of an exceptional situation, for example, when power is notswitched on to the apparatus or if the batteries have ran down, theX-ray apparatus carriage relating to the invention is provided withmeans by which the driving motors 12 can be released from being driventogether with the driving wheels 17 to allow the apparatus to be movedmanually. In the embodiment shown, these means include a release plate 7to which is attached a wire cable 9 which is connected to the jockeypulley 18 of the drive belt 15. When the driving handle is pushed orpulled considerably beyond the normal driving motion, the release plate7 pulls the wire cable 9 which in turn pulls the jockey pulley 18, thusallowing the drive belt 15 to slide over the belt pulley 14. This meansthat when the carriage is pushed or pulled, the wheels 17 are able torotate although the drive motor 12 is at a halt by itself. When releasedfrom the driving handle, the tension springs 11 press the jockey pulley18 against the drive belt 15, whereby the releasing of the drivinghandle acts as a brake due to the drive motor being at a halt by itself.When the driving handle is pulled into the normal position, it locks init. The normal driving motion of the driving handle is restricted bymeans of limit stops 5 and the movement of the release means is for itspart restricted by means of a stopper plate 8. In connection with thetoothed rim 4 are in addition preferably arranged spring members 6 whichposition the driving handle in its centre position when the grip on thedrive handle is released. The height of the driving handle is preferablyarranged so as to be adjustable.

We claim:
 1. A mobile X-ray apparatus comprising: a carriage having atleast one pair of independently driven driving wheels; motor means (12)for driving the driving wheels; a driving handle comprising a pair ofspaced side bars (2) rotatably coupled to the carnage along an axis ofrotation (3) and a cross bar movable with said side bars (1), said crossbar being coupled to and extending between the side bars in anarticulated manner to allow turning movement of the respective side barsto different extents and in different directions about the axis; andmeans that move with each turning movement of each respective side bar(2), the movement of said means being measured by a measuring means (10)which convert the measured movement into electric signals; and controlmeans receiving the electric signals for controlling the motor meansresponsive to the electrical signals to steer the carriage in a desireddirection.
 2. An X-ray apparatus as claimed in claim 1, furthercomprising means (6) for positioning the driving handle (1, 2)automatically in a centre position when the grip on the driving handleis released.
 3. An X-ray apparatus as claimed in claim 1, wherein theheight of the driving handle (1, 2) is adjustable.
 4. An X-ray apparatusas claimed in claim 1, further comprising release means (7-9) operableby movement of said driving handle to release the motor means from adriving coupling with the driving wheels (17), allowing the wheels (17)to rotate freely and thus allow manual movement of the carriage.
 5. AnX-ray apparatus as claimed in claim 2, wherein the height of the drivinghandle (1,2) is adjustable.